U.S. patent application number 16/323073 was filed with the patent office on 2021-11-18 for method for transmitting and receiving signal by terminal and base station in wireless communication system and device supporting same.
The applicant listed for this patent is LG Electronics Inc.. Invention is credited to Joonkui Ahn, Hyukjin Chae, Daesung Hwang, Seunggye Hwang, Kijun Kim, Seonwook Kim, Youngtae Kim, Kyuhwan Kwak, Seungmin Lee, Suckchel Yang.
Application Number | 20210359735 16/323073 |
Document ID | / |
Family ID | 1000005765435 |
Filed Date | 2021-11-18 |
United States Patent
Application |
20210359735 |
Kind Code |
A1 |
Kim; Seonwook ; et
al. |
November 18, 2021 |
METHOD FOR TRANSMITTING AND RECEIVING SIGNAL BY TERMINAL AND BASE
STATION IN WIRELESS COMMUNICATION SYSTEM AND DEVICE SUPPORTING
SAME
Abstract
Disclosed are a method for transmitting and receiving a signal
by a terminal and a base station and a device supporting same. More
particularly, disclosed are a method for transmitting and receiving
a signal by a base station or a terminal by means of applying a
beam-forming method which varies for each predetermined resource
region, and a device supporting same.
Inventors: |
Kim; Seonwook; (Seoul,
KR) ; Yang; Suckchel; (Seoul, KR) ; Kim;
Kijun; (Seoul, KR) ; Ahn; Joonkui; (Seoul,
KR) ; Chae; Hyukjin; (Seoul, KR) ; Kim;
Youngtae; (Seoul, KR) ; Hwang; Seunggye;
(Seoul, KR) ; Lee; Seungmin; (Seoul, KR) ;
Hwang; Daesung; (Seoul, KR) ; Kwak; Kyuhwan;
(Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG Electronics Inc. |
Seoul |
|
KR |
|
|
Family ID: |
1000005765435 |
Appl. No.: |
16/323073 |
Filed: |
August 2, 2017 |
PCT Filed: |
August 2, 2017 |
PCT NO: |
PCT/KR2017/008322 |
371 Date: |
February 4, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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62371241 |
Aug 5, 2016 |
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62443777 |
Jan 8, 2017 |
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62501068 |
May 3, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/1263 20130101;
H04B 7/0628 20130101; H04B 7/0617 20130101; H04W 72/0453 20130101;
H04W 72/0413 20130101 |
International
Class: |
H04B 7/06 20060101
H04B007/06; H04W 72/12 20060101 H04W072/12; H04W 72/04 20060101
H04W072/04 |
Claims
1. A method of transmitting an uplink signal by a user equipment
(UE) in a wireless communication system, the method comprising:
transmitting the uplink signal by applying a different beamforming
scheme to each of resource areas divided according to a
predetermined rule in one or more symbols of a slot including a
plurality of symbols.
2. The method according to claim 1, wherein the uplink signal is a
physical uplink control channel (PUCCH) or a physical uplink shared
channel (PUSCH).
3. The method according to claim 1, wherein the application of a
different beamforming scheme to each of resource areas divided
according to the predetermined rule comprises applying one or more
of digital beamforming, analog beamforming, and hybrid beamforming
differently to each of the resources areas divided according to the
predetermined rule.
4. The method according to claim 1, wherein when the uplink signal
is transmitted in one symbol, the uplink signal is transmitted by
applying a different beamforming scheme to each of the frequency
areas divided according to the predetermined rule in the one
symbol.
5. The method according to claim 4, further comprising receiving
information on the predetermined rule from a base station.
6. The method according to claim 5, wherein the information on the
predetermined rule includes one of information about the size of
frequency resources to which the same beamforming scheme is
applied, and information on a range of frequency resources to which
the same beamforming scheme is applied.
7. The method according to claim 4, wherein when the uplink signal
is mapped distributedly in the frequency domain within one symbol,
the predetermined rule indicates division of resource areas in
which a different beamforming scheme is applied to each set of
contiguous frequency resources or each set of contiguous resources
of the same comb index in the one symbol carrying the uplink
signal.
8. The method according to claim 1, wherein when the uplink signal
is transmitted in two symbols, the predetermined rule indicates
division of resource areas in which a different beamforming scheme
is applied to each symbol carrying the uplink signal.
9. The method according to claim 1, wherein when the uplink signal
is transmitted in two symbols, the predetermined rule indicates
division of resource areas in which a different beamforming scheme
is applied to each frequency resource area of a predetermined size
in the two symbols.
10. The method according to claim 1, wherein the two symbols
include a symbol including a reference signal (RS) and a symbol
without an RS.
11. The method according to claim 1, wherein when the uplink signal
is transmitted in more than two symbols, the predetermined rule
indicates division of resources areas in which a different
beamforming scheme is applied to each of a plurality of symbol
groups into which the symbols carrying the uplink signals are
grouped, and wherein each symbol group includes at least one symbol
including an RS.
12. The method according to claim 1, wherein if the uplink signal
is transmitted by frequency hopping in more than two symbols, the
predetermined rule indicates division of resource areas in which a
different beamforming scheme is applied to each hop in the more
than two symbols.
13. A user equipment (UE) for transmitting an uplink signal to a
base station (BS) in a wireless communication system, the UE
comprising: a transmitter; a receiver; and a processor operatively
connected to the transmitter and the receiver, wherein the
processor is configured to transmit the uplink signal by applying a
different beamforming scheme to each of resource areas divided
according to a predetermined rule in one or more symbols of a slot
including a plurality of symbols.
Description
TECHNICAL FIELD
[0001] The following description relates to a wireless
communication system, and more particularly, to a method of
transmitting and receiving a signal between a user equipment (UE)
and a base station (BS) in a wireless communication system, and an
apparatus supporting the same.
[0002] More specifically, the following description includes a
description of a method of transmitting and receiving a signal by
applying a different beamforming scheme to each predetermined
resource area, performed by a BS or a UE, and an apparatus
supporting the same.
[0003] Especially, the following description includes a description
of a method of transmitting an uplink control channel or an uplink
shared channel by applying a different beamforming scheme to each
time/frequency resource area according to a predetermined rule,
performed by a UE, and an apparatus supporting the same according
to the present invention.
BACKGROUND ART
[0004] Wireless access systems have been widely deployed to provide
various types of communication services such as voice or data. In
general, a wireless access system is a multiple access system that
supports communication of multiple users by sharing available
system resources (a bandwidth, transmission power, etc.) among
them. For example, multiple access systems include a Code Division
Multiple Access (CDMA) system, a Frequency Division Multiple Access
(FDMA) system, a Time Division Multiple Access (TDMA) system, an
Orthogonal Frequency Division Multiple Access (OFDMA) system, and a
Single Carrier Frequency Division Multiple Access (SC-FDMA)
system.
[0005] As a number of communication devices have required higher
communication capacity, the necessity of the mobile broadband
communication much improved than the existing radio access
technology (RAT) has increased. In addition, massive machine type
communications (MTC) capable of providing various services at
anytime and anywhere by connecting a number of devices or things to
each other has been considered in the next generation communication
system. Moreover, a communication system design capable of
supporting services/UEs sensitive to reliability and latency has
been discussed.
[0006] As described above, the introduction of the next generation
RAT considering the enhanced mobile broadband communication,
massive MTC, ultra-reliable and low latency communication (URLLC),
and the like has been discussed.
DISCLOSURE
Technical Problem
[0007] An aspect of the present invention is to provide a method of
transmitting and receiving a signal between a user equipment (UE)
and a base station (BS) in a new proposed communication system, and
an apparatus supporting the same.
[0008] Particularly, an aspect of the present invention is to
provide a method of transmitting an uplink signal in a precoder
cycling scheme which applies a different beamforming scheme to each
predetermined resource area by a UE, for efficient transmission of
the uplink signal (e.g., control information, data information,
etc.) to a BS, and an apparatus supporting the same.
[0009] It will be appreciated by persons skilled in the art that
the objects that could be achieved with the present disclosure are
not limited to what has been particularly described hereinabove and
the above and other objects that the present disclosure could
achieve will be more clearly understood from the following detailed
description.
Technical Solution
[0010] The present invention provides methods and apparatuses for
transmitting and receiving a signal by a base station (BS) and a
user equipment (UE) in a wireless communication system.
Particularly, the present invention provides methods and
apparatuses for transmitting an uplink signal to a BS by using a
different beamforming scheme (i.e., a different precoder cycling
scheme) per predetermined resource area carrying the uplink
signal.
[0011] In an aspect of the present disclosure, a method of
transmitting an uplink signal by a UE in a wireless communication
system includes transmitting the uplink signal by applying a
different beamforming scheme to each of resource areas divided
according to a predetermined rule in one or more symbols of a slot
including a plurality of symbols.
[0012] In another aspect of the present disclosure, a UE for
transmitting an uplink signal to a BS in a wireless communication
system includes a transmitter, a receiver, and a processor
operatively connected to the transmitter and the receiver. The
processor is configured to transmit the uplink signal by applying a
different beamforming scheme to each of resource areas divided
according to a predetermined rule in one or more symbols of a slot
including a plurality of symbols.
[0013] Herein, the uplink signal may be a physical uplink control
channel (PUCCH) or a physical uplink shared channel (PUSCH).
[0014] Further, in the present invention, the application of a
different beamforming scheme to each of resource areas divided
according to a predetermined rule may mean applying one or more of
digital beamforming, analog beamforming, and hybrid beamforming
differently to each of the resources areas divided according to the
predetermined rule.
[0015] In the present invention, if the uplink signal is
transmitted in one symbol, the uplink signal may be transmitted by
applying a different beamforming scheme to each of the frequency
areas divided according to the predetermined rule in the one
symbol.
[0016] The method may further include receiving information about
the predetermined rule from the BS. The information about the
predetermined rule may include one of information about the size of
frequency resources to which the same beamforming scheme is
applied, and information about a range of frequency resources to
which the same beamforming scheme is applied.
[0017] In the present invention, if the uplink signal is mapped
distributedly in the frequency domain within one symbol, the
predetermined rule may indicate division of resource areas in which
a different beamforming scheme is applied to each set of contiguous
frequency resources or each set of contiguous resources of the same
comb index in the one symbol carrying the uplink signal.
[0018] In the present invention, if the uplink signal is
transmitted in two symbols, the predetermined rule may indicate
division of resource areas in which a different beamforming scheme
is applied to each symbol carrying the uplink signal.
[0019] In the present invention, if the uplink signal is
transmitted in two symbols, the predetermined rule may indicate
division of resource areas in which a different beamforming scheme
is applied to each of a symbol including a reference signal (RS)
and a symbol without an RS.
[0020] In the present invention, if the uplink signal is
transmitted in two symbols, the predetermined rule may indicate
division of resource areas in which a different beamforming scheme
is applied to each frequency resource area of a predetermined size
in the two symbols.
[0021] In the present invention, if the uplink signal is
transmitted in more than two symbols, the predetermined rule may
indicate division of resource areas in which a different
beamforming scheme is applied to each of a symbol including an RS
and a symbol without an RS.
[0022] Further, if the uplink signal is transmitted by frequency
hopping in more than two symbols, the predetermined rule may
indicate division of resource areas in which a different
beamforming scheme is applied to each hop in the more than two
symbols.
[0023] It is to be understood that both the foregoing general
description and the following detailed description of the present
disclosure are exemplary and explanatory and are intended to
provide further explanation of the disclosure as claimed.
Advantageous Effects
[0024] As is apparent from the above description, the embodiments
of the present invention have the following effects.
[0025] According to the present invention, a UE can efficiently
transmit an uplink signal to a BS in a new proposed wireless
communication system.
[0026] Particularly according to the present invention, a UE can
efficiently transmit a physical uplink control channel (PUCCH)
including a predetermined number of symbols to a BS.
[0027] The effects that can be achieved through the embodiments of
the present invention are not limited to what has been particularly
described hereinabove and other effects which are not described
herein can be derived by those skilled in the art from the
following detailed description. That is, it should be noted that
the effects which are not intended by the present invention can be
derived by those skilled in the art from the embodiments of the
present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings, which are included to provide a
further understanding of the invention, provide embodiments of the
present invention together with detail explanation. Yet, a
technical characteristic of the present invention is not limited to
a specific drawing. Characteristics disclosed in each of the
drawings are combined with each other to configure a new
embodiment. Reference numerals in each drawing correspond to
structural elements.
[0029] FIG. 1 is a diagram illustrating physical channels and a
signal transmission method using the physical channels;
[0030] FIG. 2 is a diagram illustrating exemplary radio frame
structures;
[0031] FIG. 3 is a diagram illustrating an exemplary resource grid
for the duration of a downlink slot;
[0032] FIG. 4 is a diagram illustrating an exemplary structure of
an uplink subframe;
[0033] FIG. 5 is a diagram illustrating an exemplary structure of a
downlink subframe;
[0034] FIG. 6 is a diagram illustrating a self-contained subframe
structure applicable to the present invention;
[0035] FIGS. 7 and 8 are diagrams illustrating representative
methods for connecting TXRUs to antenna elements;
[0036] FIG. 9 is a simplified diagram illustrating a frame
structure carrying uplink data in a new radio access technology
(RAT) (NR) system to which the present invention is applicable;
[0037] FIG. 10 is a simplified diagram illustrating a transmission
diversity (TxD) transmission method according to an example of the
present invention;
[0038] FIG. 11 is a simplified diagram illustrating a TxD method in
the case of 2 antenna ports (APs)/layers used for a downlink
transmission in a legacy long term evolution (LTE) system, and FIG.
12 is a simplified diagram illustrating a TxD method in the case of
4 APs/layers used for a downlink transmission in the legacy LTE
system;
[0039] FIGS. 13 and 14 are simplified diagrams illustrating space
frequency block coding (SFBC)-based TxD transmission methods using
according to an example of the present invention;
[0040] FIG. 15 is a simplified diagram illustrating an SFBC-based
TxD transmission method according to another example of the present
invention;
[0041] FIG. 16 is a simplified diagram illustrating an SFBC-based
TxD transmission method according to another example of the present
invention;
[0042] FIG. 17 is a simplified diagram illustrating a configuration
for transmitting a phase tracking reference signal (PTRS) on one
subcarrier per PTRS AP according to an example of the present
invention; and
[0043] FIG. 18 is a block diagram of a user equipment (UE) and a
base station (BS) for implementing the proposed embodiments.
BEST MODE FOR CARRYING OUT THE INVENTION
[0044] The embodiments of the present disclosure described below
are combinations of elements and features of the present disclosure
in specific forms. The elements or features may be considered
selective unless otherwise mentioned. Each element or feature may
be practiced without being combined with other elements or
features. Further, an embodiment of the present disclosure may be
constructed by combining parts of the elements and/or features.
Operation orders described in embodiments of the present disclosure
may be rearranged. Some constructions or elements of any one
embodiment may be included in another embodiment and may be
replaced with corresponding constructions or features of another
embodiment.
[0045] In the description of the attached drawings, a detailed
description of known procedures or steps of the present disclosure
will be avoided lest it should obscure the subject matter of the
present disclosure. In addition, procedures or steps that could be
understood to those skilled in the art will not be described
either.
[0046] Throughout the specification, when a certain portion
"includes" or "comprises" a certain component, this indicates that
other components are not excluded and may be further included
unless otherwise noted. The terms "unit", "-or/er" and "module"
described in the specification indicate a unit for processing at
least one function or operation, which may be implemented by
hardware, software or a combination thereof. In addition, the terms
"a or an", "one", "the" etc. may include a singular representation
and a plural representation in the context of the present
disclosure (more particularly, in the context of the following
claims) unless indicated otherwise in the specification or unless
context clearly indicates otherwise.
[0047] In the embodiments of the present disclosure, a description
is mainly made of a data transmission and reception relationship
between a Base Station (BS) and a User Equipment (UE). A BS refers
to a terminal node of a network, which directly communicates with a
UE. A specific operation described as being performed by the BS may
be performed by an upper node of the BS.
[0048] Namely, it is apparent that, in a network comprised of a
plurality of network nodes including a BS, various operations
performed for communication with a UE may be performed by the BS,
or network nodes other than the BS. The term `BS` may be replaced
with a fixed station, a Node B, an evolved Node B (eNode B or eNB),
an Advanced Base Station (ABS), an access point, etc.
[0049] In the embodiments of the present disclosure, the term
terminal may be replaced with a UE, a Mobile Station (MS), a
Subscriber Station (SS), a Mobile Subscriber Station (MSS), a
mobile terminal, an Advanced Mobile Station (AMS), etc.
[0050] A transmission end is a fixed and/or mobile node that
provides a data service or a voice service and a reception end is a
fixed and/or mobile node that receives a data service or a voice
service. Therefore, a UE may serve as a transmission end and a BS
may serve as a reception end, on an UpLink (UL). Likewise, the UE
may serve as a reception end and the BS may serve as a transmission
end, on a DownLink (DL).
[0051] The embodiments of the present disclosure may be supported
by standard specifications disclosed for at least one of wireless
access systems including an Institute of Electrical and Electronics
Engineers (IEEE) 802.xx system, a 3rd Generation Partnership
Project (3GPP) system, a 3GPP Long Term Evolution (LTE) system, and
a 3GPP2 system. In particular, the embodiments of the present
disclosure may be supported by the standard specifications, 3GPP TS
36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS 36.321 and 3GPP TS
36.331. That is, the steps or parts, which are not described to
clearly reveal the technical idea of the present disclosure, in the
embodiments of the present disclosure may be explained by the above
standard specifications. All terms used in the embodiments of the
present disclosure may be explained by the standard
specifications.
[0052] Reference will now be made in detail to the embodiments of
the present disclosure with reference to the accompanying drawings.
The detailed description, which will be given below with reference
to the accompanying drawings, is intended to explain exemplary
embodiments of the present disclosure, rather than to show the only
embodiments that can be implemented according to the
disclosure.
[0053] The following detailed description includes specific terms
in order to provide a thorough understanding of the present
disclosure. However, it will be apparent to those skilled in the
art that the specific terms may be replaced with other terms
without departing the technical spirit and scope of the present
disclosure.
[0054] For example, the term, TxOP may be used interchangeably with
transmission period or Reserved Resource Period (RRP) in the same
sense. Further, a Listen-Before-Talk (LBT) procedure may be
performed for the same purpose as a carrier sensing procedure for
determining whether a channel state is idle or busy, CCA (Clear
Channel Assessment), CAP (Channel Access Procedure).
[0055] Hereinafter, 3GPP LTE/LTE-A systems are explained, which are
examples of wireless access systems.
[0056] The embodiments of the present disclosure can be applied to
various wireless access systems such as Code Division Multiple
Access (CDMA), Frequency Division Multiple Access (FDMA), Time
Division Multiple Access (TDMA), Orthogonal Frequency Division
Multiple Access (OFDMA), Single Carrier Frequency Division Multiple
Access (SC-FDMA), etc.
[0057] CDMA may be implemented as a radio technology such as
Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be
implemented as a radio technology such as Global System for Mobile
communications (GSM)/General packet Radio Service (GPRS)/Enhanced
Data Rates for GSM Evolution (EDGE). OFDMA may be implemented as a
radio technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX),
IEEE 802.20, Evolved UTRA (E-UTRA), etc.
[0058] UTRA is a part of Universal Mobile Telecommunications System
(UMTS). 3GPP LTE is a part of Evolved UMTS (E-UMTS) using E-UTRA,
adopting OFDMA for DL and SC-FDMA for UL. LTE-Advanced (LTE-A) is
an evolution of 3GPP LTE. While the embodiments of the present
disclosure are described in the context of a 3GPP LTE/LTE-A system
in order to clarify the technical features of the present
disclosure, the present disclosure is also applicable to an IEEE
802.16e/m system, etc.
1. 3GPP LTE/LTE-A System
[0059] 1.1 Physical Channels and Method of Transmitting and
Receiving Signals on the Physical Channels
[0060] In a wireless access system, a UE receives information from
an eNB on a DL and transmits information to the eNB on a UL. The
information transmitted and received between the UE and the eNB
includes general data information and various types of control
information. There are many physical channels according to the
types/usages of information transmitted and received between the
eNB and the UE.
[0061] FIG. 1 illustrates physical channels and a general signal
transmission method using the physical channels, which may be used
in embodiments of the present disclosure.
[0062] When a UE is powered on or enters a new cell, the UE
performs initial cell search (S11). The initial cell search
involves acquisition of synchronization to an eNB. Specifically,
the UE synchronizes its timing to the eNB and acquires information
such as a cell Identifier (ID) by receiving a Primary
Synchronization Channel (P-SCH) and a Secondary Synchronization
Channel (S-SCH) from the eNB.
[0063] Then the UE may acquire information broadcast in the cell by
receiving a Physical Broadcast Channel (PBCH) from the eNB.
[0064] During the initial cell search, the UE may monitor a DL
channel state by receiving a Downlink Reference Signal (DL RS).
[0065] After the initial cell search, the UE may acquire more
detailed system information by receiving a Physical Downlink
Control Channel (PDCCH) and receiving a Physical Downlink Shared
Channel (PDSCH) based on information of the PDCCH (S12).
[0066] To complete connection to the eNB, the UE may perform a
random access procedure with the eNB (S13 to S16). In the random
access procedure, the UE may transmit a preamble on a Physical
Random Access Channel (PRACH) (S13) and may receive a PDCCH and a
PDSCH associated with the PDCCH (S14). In the case of
contention-based random access, the UE may additionally perform a
contention resolution procedure including transmission of an
additional PRACH (S15) and reception of a PDCCH signal and a PDSCH
signal corresponding to the PDCCH signal (S16).
[0067] After the above procedure, the UE may receive a PDCCH and/or
a PDSCH from the eNB (S17) and transmit a Physical Uplink Shared
Channel (PUSCH) and/or a Physical Uplink Control Channel (PUCCH) to
the eNB (S18), in a general UL/DL signal transmission
procedure.
[0068] Control information that the UE transmits to the eNB is
generically called Uplink Control Information (UCI). The UCI
includes a Hybrid Automatic Repeat and reQuest
Acknowledgement/Negative Acknowledgement (HARQ-ACK/NACK), a
Scheduling Request (SR), a Channel Quality Indicator (CQI), a
Precoding Matrix Index (PMI), a Rank Indicator (RI), etc.
[0069] In the LTE system, UCI is generally transmitted on a PUCCH
periodically. However, if control information and traffic data
should be transmitted simultaneously, the control information and
traffic data may be transmitted on a PUSCH. In addition, the UCI
may be transmitted aperiodically on the PUSCH, upon receipt of a
request/command from a network.
[0070] 1.2. Resource Structure
[0071] FIG. 2 illustrates exemplary radio frame structures used in
embodiments of the present disclosure.
[0072] FIG. 2(a) illustrates frame structure type 1. Frame
structure type 1 is applicable to both a full Frequency Division
Duplex (FDD) system and a half FDD system.
[0073] One radio frame is 10 ms (Tf=307200Ts) long, including
equal-sized 20 slots indexed from 0 to 19. Each slot is 0.5 ms
(Tslot=15360Ts) long. One subframe includes two successive slots.
An ith subframe includes 2ith and (2i+1)th slots. That is, a radio
frame includes 10 subframes. A time required for transmitting one
subframe is defined as a Transmission Time Interval (TTI). Ts is a
sampling time given as Ts=1/(15 kHz.times.2048)=3.2552.times.10-8
(about 33 ns). One slot includes a plurality of Orthogonal
Frequency Division Multiplexing (OFDM) symbols or SC-FDMA symbols
in the time domain by a plurality of Resource Blocks (RBs) in the
frequency domain.
[0074] A slot includes a plurality of OFDM symbols in the time
domain. Since OFDMA is adopted for DL in the 3GPP LTE system, one
OFDM symbol represents one symbol period. An OFDM symbol may be
called an SC-FDMA symbol or symbol period. An RB is a resource
allocation unit including a plurality of contiguous subcarriers in
one slot.
[0075] In a full FDD system, each of 10 subframes may be used
simultaneously for DL transmission and UL transmission during a
10-ms duration. The DL transmission and the UL transmission are
distinguished by frequency. On the other hand, a UE cannot perform
transmission and reception simultaneously in a half FDD system.
[0076] The above radio frame structure is purely exemplary. Thus,
the number of subframes in a radio frame, the number of slots in a
subframe, and the number of OFDM symbols in a slot may be
changed.
[0077] FIG. 2(b) illustrates frame structure type 2. Frame
structure type 2 is applied to a Time Division Duplex (TDD) system.
One radio frame is 10 ms (Tf=307200Ts) long, including two
half-frames each having a length of 5 ms (=153600Ts) long. Each
half-frame includes five subframes each being 1 ms (=30720Ts) long.
An ith subframe includes 2ith and (2i+1)th slots each having a
length of 0.5 ms (Tslot=15360Ts). Ts is a sampling time given as
Ts=1/(15 kHz.times.2048)=3.2552.times.10-8 (about 33 ns).
[0078] A type-2 frame includes a special subframe having three
fields, Downlink Pilot Time Slot (DwPTS), Guard Period (GP), and
Uplink Pilot Time Slot (UpPTS). The DwPTS is used for initial cell
search, synchronization, or channel estimation at a UE, and the
UpPTS is used for channel estimation and UL transmission
synchronization with a UE at an eNB. The GP is used to cancel UL
interference between a UL and a DL, caused by the multi-path delay
of a DL signal.
[0079] [Table 1] below lists special subframe configurations
(DwPTS/GP/UpPTS lengths).
TABLE-US-00001 TABLE 1 Normal cyclic prefix in downlink Extended
cyclic prefix in downlink UpPTS UpPTS Normal Extended Normal
Extended Special subframe cyclic prefix cyclic prefix cyclic prefix
cyclic prefix configuration DwPTS in uplink in uplink DwPTS in
uplink in uplink 0 6592 T.sub.s 2192 T.sub.s 2560 T.sub.s 7680
T.sub.s 2192 T.sub.s 2560 T.sub.s 1 19760 T.sub.s 20480 T.sub.s 2
21952 T.sub.s 23040 T.sub.s 3 24144 T.sub.s 25600 T.sub.s 4 26336
T.sub.s 7680 T.sub.s 5 6592 T.sub.s 4384 T.sub.s 5120 T.sub.s 20480
T.sub.s 4384 T.sub.s 5120 T.sub.s 6 19760 T.sub.s 23040 T.sub.s 7
21952 T.sub.s -- -- -- 8 24144 T.sub.s -- -- --
[0080] FIG. 3 illustrates an exemplary structure of a DL resource
grid for the duration of one DL slot, which may be used in
embodiments of the present disclosure.
[0081] Referring to FIG. 3, a DL slot includes a plurality of OFDM
symbols in the time domain. One DL slot includes 7 OFDM symbols in
the time domain and an RB includes 12 subcarriers in the frequency
domain, to which the present disclosure is not limited.
[0082] Each element of the resource grid is referred to as a
Resource Element (RE). An RB includes 12.times.7 REs. The number of
RBs in a DL slot, NDL depends on a DL transmission bandwidth. The
structure of the uplink slot may be the same as the structure of
the downlink slot.
[0083] FIG. 4 illustrates a structure of a UL subframe which may be
used in embodiments of the present disclosure.
[0084] Referring to FIG. 4, a UL subframe may be divided into a
control region and a data region in the frequency domain. A PUCCH
carrying UCI is allocated to the control region and a PUSCH
carrying user data is allocated to the data region. To maintain a
single carrier property, a UE does not transmit a PUCCH and a PUSCH
simultaneously. A pair of RBs in a subframe are allocated to a
PUCCH for a UE. The RBs of the RB pair occupy different subcarriers
in two slots. Thus it is said that the RB pair frequency-hops over
a slot boundary.
[0085] FIG. 5 illustrates a structure of a DL subframe that may be
used in embodiments of the present disclosure.
[0086] Referring to FIG. 5, up to three OFDM symbols of a DL
subframe, starting from OFDM symbol 0 are used as a control region
to which control channels are allocated and the other OFDM symbols
of the DL subframe are used as a data region to which a PDSCH is
allocated. DL control channels defined for the 3GPP LTE system
include a Physical Control Format Indicator Channel (PCFICH), a
PDCCH, and a Physical Hybrid ARQ Indicator Channel (PHICH).
[0087] The PCFICH is transmitted in the first OFDM symbol of a
subframe, carrying information about the number of OFDM symbols
used for transmission of control channels (i.e. the size of the
control region) in the subframe. The PHICH is a response channel to
a UL transmission, delivering an HARQ ACK/NACK signal. Control
information carried on the PDCCH is called Downlink Control
Information (DCI). The DCI transports UL resource assignment
information, DL resource assignment information, or UL Transmission
(Tx) power control commands for a UE group.
2. New Radio Access Technology System
[0088] As more and more communication devices require greater
communication capacity, there is a need for mobile broadband
communication enhanced over existing radio access technology (RAT).
In addition, massive Machine-Type Communications (MTC) capable of
providing a variety of services anywhere and anytime by connecting
multiple devices and objects is also considered. Communication
system design considering services/UEs sensitive to reliability and
latency is also under discussion.
[0089] Thus, introduction of a new radio access technology
considering enhanced mobile broadband communication, massive MTC,
and Ultra-Reliable and Low Latency Communication (URLLC) is being
discussed. In the present invention, for simplicity, this
technology will be referred to as New RAT or NR (New Radio).
[0090] 2.1. Self-Contained Subframe Structure
[0091] FIG. 6 is a diagram illustrating a self-contained subframe
structure applicable to the present invention.
[0092] In the NR system to which the present invention is
applicable, a self-contained subframe structure as shown in FIG. 6
is proposed in order to minimize data transmission latency in the
TDD system.
[0093] In FIG. 6, the hatched region (e.g., symbol index=0)
represents a downlink control region, and the black region (e.g.,
symbol index=13) represents an uplink control region. The other
region (e.g., symbol index=1 to 12) may be used for downlink data
transmission or for uplink data transmission.
[0094] In this structure, DL transmission and UL transmission may
be sequentially performed in one subframe. In addition, DL data may
be transmitted and received in one subframe and UL ACK/NACK
therefor may be transmitted and received in the same subframe. As a
result, this structure may reduce time taken to retransmit data
when a data transmission error occurs, thereby minimizing the
latency of final data transmission.
[0095] In such a self-contained subframe structure, a time gap
having a certain time length is required in order for the base
station and the UE to switch from the transmission mode to the
reception mode or from the reception mode to the transmission mode.
To this end, some OFDM symbols at the time of switching from DL to
UL in the self-contained subframe structure may be set as a guard
period (GP).
[0096] While a case where the self-contained subframe structure
includes both the DL control region and the UL control region has
been described above, the control regions may be selectively
included in the self-contained subframe structure. In other words,
the self-contained subframe structure according to the present
invention may include not only the case of including both the DL
control region and the UL control region but also the case of
including either the DL control region or the UL control region
alone as shown in FIG. 6.
[0097] For simplicity of explanation, the frame structure
configured as above is referred to as a subframe, but this
configuration can also be referred to as a frame or a slot. For
example, in the NR system, one unit consisting of a plurality of
symbols may be referred to as a slot. In the following description,
a subframe or a frame may be replaced with the slot described
above.
[0098] 2.2. OFDM Numerology
[0099] The NR system uses the OFDM transmission scheme or a similar
transmission scheme. Here, the NR system may typically have the
OFDM numerology as shown in Table 2.
TABLE-US-00002 TABLE 2 Parameter Value Subcarrier-spacing
(.DELTA.f) 75 kHz OFDM symbol length 13.33 .mu.s Cyclic Prefix(CP)
length 1.04 us/0.94 .mu.s System BW 100 MHz No. of available
subcarriers 1200 Subframe length 0.2 ms Number of OFDM symbol per
Subframe 14 symbols
[0100] Alternatively, the NR system may use the OFDM transmission
scheme or a similar transmission scheme, and may use an OFDM
numerology selected from among multiple OFDM numerologies as shown
in Table 3. Specifically, as disclosed in Table 3, the NR system
may take the 15 kHz subcarrier-spacing used in the LTE system as a
base, and use an OFDM numerology having subcarrier-spacing of 30,
60, and 120 kHz, which are multiples of the 15 kHz
subcarrier-spacing.
[0101] In this case, the cyclic prefix, the system bandwidth (BW)
and the number of available subcarriers disclosed in Table 3 are
merely an example that is applicable to the NR system according to
the present invention, and the values thereof may vary depending on
the implementation method. Typically, for the 60 kHz
subcarrier-spacing, the system bandwidth may be set to 100 MHz. In
this case, the number of available subcarriers may be greater than
1500 and less than 1666. Also, the subframe length and the number
of OFDM symbols per subframe disclosed in Table 3 are merely an
example that is applicable to the NR system according to the
present invention, and the values thereof may vary depending on the
implementation method.
TABLE-US-00003 TABLE 3 Parameter Value Value Value Value
Subcarrier-spacing 15 kHz 30 kHz 60 kHz 120 kHz (.DELTA.f) OFDM
symbol length 66.66 33.33 16.66 8.33 Cyclic Prefix(CP) length 5.20
.mu.s/4.69 .mu.s 2.60 .mu.s/2.34 .mu.s 1.30 .mu.s/1.17 .mu.s 0.65
.mu.s/0.59 .mu.s System BW 20 MHz 40 MHz 80 MHz 160 MHz No. of
available 1200 1200 1200 1200 subcarriers Subframe length 1 ms 0.5
ms 0.25 ms 0.125 ms Number of OFDM 14 symbols 14 symbols 14 symbols
14 symbols symbol per Subframe
[0102] 2.3. Analog Beamforming
[0103] In a millimeter wave (mmW) system, since a wavelength is
short, a plurality of antenna elements can be installed in the same
area. That is, considering that the wavelength at 30 GHz band is 1
cm, a total of 100 antenna elements can be installed in a 5*5 cm
panel at intervals of 0.5 lambda (wavelength) in the case of a
2-dimensional array. Therefore, in the mmW system, it is possible
to improve the coverage or throughput by increasing the beamforming
(BF) gain using multiple antenna elements.
[0104] In this case, each antenna element can include a transceiver
unit (TXRU) to enable adjustment of transmit power and phase per
antenna element. By doing so, each antenna element can perform
independent beamforming per frequency resource.
[0105] However, installing TXRUs in all of the about 100 antenna
elements is less feasible in terms of cost. Therefore, a method of
mapping a plurality of antenna elements to one TXRU and adjusting
the direction of a beam using an analog phase shifter has been
considered. However, this method is disadvantageous in that
frequency selective beamforming is impossible because only one beam
direction is generated over the full band.
[0106] To solve this problem, as an intermediate form of digital BF
and analog BF, hybrid BF with B TXRUs that are fewer than Q antenna
elements can be considered. In the case of the hybrid BF, the
number of beam directions that can be transmitted at the same time
is limited to B or less, which depends on how B TXRUs and Q antenna
elements are connected.
[0107] FIGS. 7 and 8 are diagrams illustrating representative
methods for connecting TXRUs to antenna elements. Here, the TXRU
virtualization model represents the relationship between TXRU
output signals and antenna element output signals.
[0108] FIG. 7 shows a method for connecting TXRUs to sub-arrays. In
FIG. 7, one antenna element is connected to one TXRU.
[0109] Meanwhile, FIG. 8 shows a method for connecting all TXRUs to
all antenna elements. In FIG. 8, all antenna element are connected
to all TXRUs. In this case, separate addition units are required to
connect all antenna elements to all TXRUs as shown in FIG. 8.
[0110] In FIGS. 7 and 8, W indicates a phase vector weighted by an
analog phase shifter. That is, W is a major parameter determining
the direction of the analog beamforming. In this case, the mapping
relationship between CSI-RS antenna ports and TXRUs may be 1:1 or
1-to-many
[0111] The configuration shown in FIG. 7 has a disadvantage in that
it is difficult to achieve beamforming focusing but has an
advantage in that all antennas can be configured at low cost.
[0112] On the contrary, the configuration shown in FIG. 8 is
advantageous in that beamforming focusing can be easily achieved.
However, since all antenna elements are connected to the TXRU, it
has a disadvantage of high cost.
[0113] 3. Proposed Embodiments
[0114] FIG. 9 is a simplified diagram illustrating a frame
structure carrying UL data in a new RAT (NR) system to which the
present invention is applicable. A transmission time interval (TTI)
may be defined as a minimum time interval during which the medium
access control (MAC) layer transmits MAC protocol data units (PDUs)
to the physical (PHY) layer. While it is assumed that one TTI
includes 14 symbols in FIG. 9, the TTI may be configured to have a
longer or shorter time length.
[0115] In FIG. 9, a NewRAT physical downlink control channel
(NR-PDCCH) refers to a DL control channel carrying DL/UL scheduling
information, a NewRAT physical uplink shared channel (NR-PUSCH)
refers to a UL channel carrying UL data, and a NewRAT physical
uplink control channel (NR-PUCCH) refers to a UL control channel
carrying information such as hybrid automatic repeat
request-acknowledgement (HARQ-ACK/channel state information (CSI).
In addition, a demodulation reference signal (DM-RS) refers to a
signal used for channel estimation performed to demodulate the
NR-PUSCH.
[0116] As illustrated in FIG. 9, each signal/channel may be
transmitted in a specific symbol(s), and on a different subcarrier
per antenna port (AP). Herein, each signal/channel may be
transmitted through up to 4 APs.
[0117] A phase noise compensation reference signal (PCRS)/phase
tracking reference signal (PTRS) (hereinafter, referred to
collectively as a PTRS) refers to a signal transmitted in addition
to the DM-RS in order to help with channel estimation in
consideration of high mobility or the phase noise of an oscillator.
As illustrated in FIG. 9, the PTRS may be configured to be
transmitted on a specific subcarrier(s), and in a different
symbol/on a different subcarrier per AP. While configurations
applicable to the present invention are proposed on the basis of
the basic frame structure illustrated in FIG. 9 for the convenience
of description, those skilled in the art will clearly understand
that the configurations are also applicable to frame structures
which differ from the frame structure of FIG. 9 in terms of the
transmission resource areas and positions of an NR-PDCCH, a guard
period, an NR-PUSCH, an NR-PUCCH, a PTRS, and a DM-RS.
[0118] Hereinbelow, methods of transmitting an NR-PUSCH in transmit
diversity, methods of transmitting an NR-PUCCH in transmit
diversity, methods of multiplexing a DM-RS/PCRS with an NR-PUSCH,
and so on will be proposed on the basis of the above-described
frame structure.
[0119] 3.1. NR-PUSCH Transmit Diversity (TxD)
[0120] As a DL transmission method using a plurality of APs, the
legacy LTE(-A) system supports both of a TxD-based method and a
spatial multiplexing (SM)-based method. However, the legacy LTE(-A)
system supports only an SM-based method for UL transmission.
[0121] In consideration of a larger number of APs of a UE than that
of a legacy LTE UE, supported by an NR system to which the present
invention is applicable, transmission of UL data for which it is
important to guarantee reliability, or coverage expansion of
cell-edge UEs, the NR system may also support a TxD transmission
method for UL transmission.
[0122] Accordingly, a detailed description will be given of a
method of indicating TxD transmission of an NR-PUSCH to a UE, and a
method of transmitting an NR-PUSCH in TxD in this section.
[0123] The following description is given of a related
configuration, focusing on the NR-PUSCH, with the appreciation that
the TxD indicating method and the TxD transmission method are also
applicable in the same manner to other channels. For example, TxD
for the NR-PDSCH/NR-PUSCH may be indicated by a DL grant in methods
proposed in section 3.1.1 below. In another example, the TxD
transmission method is also applicable in the same manner to the
NR-PDCCH/NR-PDSCH/NR-PUCCH.
[0124] 3.1.1. TxD Indication Methods
[0125] (1) Method of indicating TxD by DCI (or physical-layer
signaling)
[0126] Preferably, it may be indicated dynamically whether to
transmit UL data in a TxD transmission method or an SM transmission
method according to the channel state of a UE or the service type
of the UL data.
[0127] For example, information indicating TxD may be jointly
encoded with scheduling information indicating a precoding matrix
used for SM. Specifically, a new generation Node B (gNB) may
indicate TxD by some state of a field in DCI indicating a precoding
matrix (or a codebook index) and the number of layers.
Additionally, the gNB may indicate how many APs/layers or which APs
are used for TxD by an additional field or another state of the
above-described field.
[0128] For the convenience of description, a BS operating in the NR
system according to the present invention is referred to as a gNB,
distinguishably from an eNB which is an exemplary LTE BS. However,
the term gNB may be replaced with eNB depending on an
implementation example.
[0129] In another example, the gNB may differentiate DCI formats
for TxD transmission and SM transmission, and accordingly indicate
TxD or SM to a UE by a DCI format indicator.
[0130] (2) Method of indicating TxD by higher-layer signaling (e.g.
RRC signaling)
[0131] If the channel state of a UE does not fluctuate or the
quality of service (QoS) level of UL data that the UE transmits is
similar during a predetermined time, the gNB may semi-statically
indicate TxD or SM by RRC signaling.
[0132] 3.1.2. TxD Transmission Method (Other Than SFBC (Space
Frequency Block Code))
[0133] The legacy LTE system adopts SFBC as a TxD transmission
method for DL transmission. This method is designed so as to
achieve an optimum diversity gain for 2Tx1Rx (i.e., 2 Txs and 1
Rx). For more than 2 APs at a transmission node, it is difficult to
maximize the diversity gain with the method. Especially,
considering that the number of APs at an NR UE supported by the NR
system to which the present invention is applicable may be larger
than 2, the present invention proposes a TxD transmission method to
increase the diversity gain of UL transmission.
[0134] First, the basic idea of the present invention is to achieve
a spatial-domain multiplexing gain by multiplying a signal by a
(quasi-)orthogonal sequence per AP, prior to transmission. An
orthogonal sequence of length k (k is the number of transmission
APs) is multiplied across (non-)contiguous k resources along the
frequency axis (or the time axis), and the same modulated symbol is
repeatedly transmitted in the k resources.
[0135] FIG. 10 is a simplified diagram illustrating a TxD
transmission method according to an example of the present
invention.
[0136] As illustrated in FIG. 10, for example, a TxD method with 4
APs may be used as a UL signal transmission method. Since a UL
signal is transmitted through the 4 APs, the same modulated symbol
(e.g., "a" in FIG. 10) is repeatedly mapped to 4 subcarriers, and a
length-4 orthogonal sequence (e.g., Hadamard sequence) is
multiplied by the symbols on the subcarriers, for each AP (or
layer). To guarantee the single carrier-frequency division
multiplexing (SC-FDM) property, this process needs to be performed
before discrete Fourier transform (DFT). If OFDM is adopted for UL
transmission, the process may be performed before or after inverse
fast Fourier transform (IFFT). While examples of using 4
subcarriers are presented for the illustrative purpose in the above
description, the configuration of the present invention may be
extended to a case in which UL data is transmitted on more
subcarriers. In this case, subcarriers may be grouped into groups
each including 4 subcarriers, and an operation of the present
invention may be performed in units of 4 subcarriers.
[0137] In FIG. 10, when an NR-PUSCH is transmitted in a 4-AP TxD
method, 4 subcarriers may form one transmission group. If a PTRS is
transmitted on a specific subcarrier(s), it may be difficult to
group subcarriers by fours.
[0138] Regarding N (N<4) subcarriers excluded from grouping, a
symbol may be transmitted repeatedly on the N subcarriers in the
same manner as N APs transmit signals in TxD, and a length-N
orthogonal sequence may be multiplied by the symbols. For example,
if the PTRS is transmitted in the manner illustrated in FIG. 9,
subcarriers #0, #1, #2 and #3, and subcarriers #8, #9, #10 and #11
are grouped respectively, with subcarriers #5 and #6 paired. Then,
a signal may be transmitted on subcarriers #5 and #6 in TxD only
through two APs, AP #1 and AP #2.
[0139] The above description may further be extended such that when
a length-k orthogonal sequence (k is the number of transmission
APs) is multiplied across (non-) contiguous k resources on the
frequency axis (or the time axis), the same modulated symbol may be
repeatedly transmitted in the k resources, or k or fewer modulated
symbols may be transmitted in the k resources. For example, in the
example of FIG. 10, a modulated symbol "a" may be repeatedly
transmitted in layers #1 and #2, whereas a modulation symbol "b"
may be repeatedly transmitted in layers #3 and #4.
[0140] Unlike the above method, when a length-k orthogonal sequence
is multiplied across (non-)contiguous k resources on the frequency
axis (or the time axis), k may be larger than the number of
transmission APs. In this case, the same modulated symbol may be
repeatedly transmitted or different modulated symbols may be
transmitted in code division multiplexing (CDM), in a specific
layer.
[0141] Characteristically, the afore-proposed various TxD methods
and TxD methods proposed in section 3.1.3 below may be configured
differently according to modulation orders, modulation and coding
schemes (MCSs), use cases/services, or the like. For example, in
this section, as the modulation order increases, a peak-to-average
power ratio (PAPR) also increases. Thus, a TxD method simply using
a codebook of an identity matrix may be applied for an MCS equal to
or larger than a predetermined value. In another example, as the
modulation order increases, a TxD method with a smaller repetition
number may be applied in this section.
[0142] 3.1.3. TxD Transmission Methods Using SFBC
[0143] In the legacy LTE system, a TxD method for DL transmission
is implemented in SFBC. Particularly, SFBC-based Tx transmission
methods are defined for 2 APs/layers, and 4 APs/layers in the LTE
system.
[0144] FIG. 11 is a simplified diagram illustrating a TxD method in
the case of 2 APs/layers for DL transmission in the legacy LTE
system, and FIG. 12 is a simplified diagram illustrating a TxD
method in the case of 4 APs/layers for DL transmission in the
legacy LTE system.
[0145] As illustrated in FIG. 11, in the case of 2 APs/layers, for
4 modulated symbols {C1, C2, C3, C4} mapped to 4 respective
subcarriers, every two adjacent ones of the 4 subcarriers are
paired and SFBC is applied to each of the pairs. As illustrated in
FIG. 12, in the case of 4 APs/layers, SFBC is applied to a {C1, C2}
pair through APs #1 and #3, and SFBC is applied to a {C3, C4} pair
through APs #2 and #4.
[0146] 3.1.3.1. Method 1
[0147] If the method illustrated in FIG. 11 is applied to UL
transmission, the PAPR performance of layer 1 may be same in
consideration of SC-FDM. However, for layer 2, the single carrier
property is not maintained, thereby degrading PAPR performance. In
this section, a method of overcoming the problem is proposed.
[0148] The basic idea proposed in this section is that when
subcarriers are paired, non-contiguous subcarriers are paired,
instead of contiguous subcarriers.
[0149] FIGS. 13 and 14 are simplified diagrams illustrating
SFBC-based TxD transmission methods according to an example of the
present invention.
[0150] FIG. 13 illustrates an SFBC scheme applied to the above
first example. According to the first example, as illustrated in
FIG. 13, when two paired symbols are mapped in each of layers, the
pair is mapped with one of the symbols "conjugated" in one of the
layers, while the two symbols are swapped in position, with the
other symbol "conjugated" in the other layer.
[0151] As such, SFBC is applied as illustrated in FIG. 13 in the
SFBC-based TxD transmission method according to the first example
of the present invention. Further, as illustrated in FIG. 14, with
{C1, C3} and {C2, C4} paired respectively, SFBC may be applied on a
pair basis. In this manner, every two of symbols, which are apart
from each other by a subcarrier spacing of M subcarriers, may be
paired and subjected to SFBC. M may be set by physical-layer
signaling or higher-layer signaling. The above method is also
applicable in the same manner to a case of more than 2
APs/layers.
[0152] 3.1.3.2. Method 2
[0153] Meanwhile, the mapping relationship between a coded bit
stream and APs/layers is fixed for DL, so it is not to be changed
on the time/frequency axis in the legacy LTE system. This
configuration may advantageously increase a diversity gain by
permuting the mapping relationship on the time/frequency axis.
[0154] FIG. 15 is a simplified diagram illustrating an SFBC-based
TxD transmission method according to another example of the present
invention.
[0155] As illustrated in FIG. 15, SFBC may be applied to a {C1, C2}
pair through APs #1 and #2, while SFBC may be applied to a {C3, C4}
pair through APs #3 and #4.
[0156] Additionally, both of the SFBC method illustrated in FIG. 15
and the SFBC method illustrated in FIG. 12 may be applied in the
present invention. Each of the SFBC methods may be performed in a
predetermined rule or a rule indicated by physical-layer signaling
or higher-layer signaling.
[0157] For example, the SFBC method illustrated in FIG. 15 may be
applied to even-numbered symbols, while the SFBC method illustrated
in FIG. 12 may be applied to odd-numbered symbols.
[0158] In another example, the SFBC method illustrated in FIG. 15
and the SFBC method illustrated in FIG. 12 may be applied
alternately every four subcarriers in an allocated frequency
resource area within the same symbol. Additionally, aside from the
afore-described two SFBC methods, various combinations of mapping
methods are available for mapping the {C1, C2} pair and the {C3,
C4} pair to APs.
[0159] 3.1.3.3. Method 3
[0160] The proposed TxD transmission methods have been described in
section 3.1.3.1. and section 3.1.3.2. with the appreciation that
SFBC is applied only on the frequency axis. However, the TxD
transmission methods applicable to the present invention may be
extended to TxD transmission methods in which SFC is applied on the
time and frequency axes in combination.
[0161] FIG. 16 is a simplified diagram illustrating an SFBC-based
TxD transmission method according to another example of the present
invention.
[0162] For example, as illustrated in FIG. 16, while only APs #1
and #3 are selected and SFBC is applied to a pair of {C1, C2} in
symbol #3, while only APs #2 and #4 are selected and SFBC is
applied to a pair of {C3, C4} in symbol #4.
[0163] Additionally, Method 3 is advantageous in that a resource
area used for PTRS transmission may be reduced.
[0164] FIG. 17 is a simplified diagram illustrating a configuration
for transmitting a PTRS on one subcarrier per PTRS AP according to
an example of the present invention.
[0165] As illustrated in FIG. 17, if a PTRS is transmitted on one
(or more) subcarriers per PTRS AP, there is no need for
transmitting PTRSs of all PTRS APs in one symbol in the case of TxD
using only APs #1 and #3 or APs #2 and #4 in one symbol as
illustrated in FIG. 16. In other words, a PTRS may be transmitted
in symbol #3 only through APs #1 and #3, while a PTRS may be
transmitted in symbol #4 only through APs #2 and #4.
[0166] Characteristically, a specific transmission method (e.g.,
PTRS AP mapping, the number of transmission subcarriers, etc.) may
be changed depending on whether a PTRS is transmitted in SM or TxD.
For example, when a gNB transmits the PTRS in SM (or through a
single AP), the gNB may transmit the PTRS in the manner illustrated
in FIG. 17, and when the gNB transmits the PTRS in TxD, the gNB may
transmit the PTRS in the manner illustrated in FIG. 9.
[0167] Further, if the PTRS is transmitted in the TxD method
proposed in this section, PTRS APs that transmit the PTRS in each
symbol may be determined according to APs that actually attempt
data transmission in the symbol. For example, if SFBC is applied to
APs #1 and #3 for data transmission, the PTRS may also be
transmitted through APs #1 and #3.
[0168] On the contrary, if PTRS-AP mapping is preset for a specific
resource area as illustrated in FIG. 9, SFBC may be applied to each
symbol by using two predetermined APs. In a more specific example,
if the PTRS is configured to be transmitted in a specific symbol
through APs #1 and #3, SFBC may also be applied to data transmitted
in the symbol by using only APs #1 and #3.
[0169] In the TxD method proposed in this section, it may be
configured that each modulated symbol is transmitted through all
APs.
[0170] For example, it may be configured that the {C3, C4} pair is
replaced with the {C1, C2} pair, and thus the {C1, C2} pair is
transmitted through all APs in FIG. 12.
[0171] In another example, it may be configured that the {C3, C4}
pair is replaced with the {C1, C2} pair, and thus the {C1, C2} pair
is transmitted through all APs in FIG. 16.
[0172] In another example, it may be configured that the {C3, C4}
pair is replaced with the {C1, C2} pair, and the {C1, C2} pair is
transmitted through all APs in FIG. 16.
[0173] 3.2. NR-PUCCH Transmit Diversity (TxD)
[0174] In the NR system to which the present invention is
applicable, a new PUCCH may be defined to carry UCI including an
HARQ-ACK and/or CSI and/or beam-related information and/or
scheduling request (SR)-related information. For the convenience of
description, the new proposed PUCCH will be referred to as an
NR-PUCCH.
[0175] The NR-PUCCH may include a relatively short PUCCH including
one or two symbols (referred to as a 1-symbol PUCCH or a 2-symbol
PUCCH), or a relatively long PUCCH including 4 or more symbols
(referred to as a long PUCCH) in a slot with 14 (or 7) symbols.
[0176] In this section, a precoder cycling-based TxD method for
each of the NR-PUCCHs will be described in detail. Precoder cycling
may mean that a different one of digital beamforming, analog
beamforming, and hybrid beamforming is performed on a predetermined
time or frequency area basis. Further, the precoder cycling may
include antenna switching and/or panel switching.
[0177] While a configuration of the present invention will be
described below, focusing on the NR-PUCCH, the TxD transmission
method proposed by the present invention may also be applied in the
same manner to other channels (e.g., NR-PDCCH, NR-PDSCH, and
NR-PUSCH).
[0178] 3.2.1. 1-Symbol PUCCH TxD Method
[0179] To transmit a 1-symbol PUCCH in TxD, it may be configured
that the same precoding/beamforming is applied on a specific
frequency unit (e.g., RE group or RB group) basis.
[0180] For example, different precoding/beamforming may be applied
to a 1-symbol PUCCH having 10 RBs every 5 RBs (preset or configured
by L1 signaling or higher-layer signaling).
[0181] In another example, when the 1-symbol PUCCH is subjected to
distributed mapping, but localized mapping, the same
precoding/beamforming may be configured for (or applied to) the
1-symbol PUCCH, only within contiguous frequency resources (or
contiguous resources of the same comb index).
[0182] In another example, precoding/beamforming applied to a
specific frequency unit may be determined by an actually mapped
frequency-domain resource index irrespective of the amount of
allocated frequency resources. In a specific example, if a 100-RB
band is divided into frequency bands each having 10 RBs, the same
precoding/beamforming may be applied only to frequency resources
within the same frequency band in the allocated 1-symbol PUCCH.
[0183] In another example, if both of an RS and UCI are included in
the single symbol, the same precoding/beamforming may be configured
for (or applied to) a frequency area in which the RS includes a
predetermined number of or more REs (preset or configured by L1
signaling or higher-layer signaling).
[0184] Meanwhile, if an RS and/or UCI are sequences, a sequence as
long as the number of corresponding REs may be generated in a
frequency area to which the same precoding/beamforming is
applied.
[0185] The method described above in this section may be applied
commonly to a PUCCH structure with an RS and UCI multiplexed in
frequency division multiplexing (FDM), and a PUCCH structure
transmitted without an RS by sequence selection.
[0186] 3.2.2. 2-Symbol PUCCH TxD Method
[0187] For example, if the 2-symbol PUCCH structure is an extension
of the afore-described 1-symbol PUCCH structure, a 2-symbol PUCCH
may be transmitted by applying the foregoing 1-symbol PUCCH TxD
method to each symbol.
[0188] In another example, the same or different
precoding/beamforming may be applied to two symbols. Particularly,
a configuration of applying the same precoding/beamforming to two
symbols may be applied to a case in which the first and second
symbols have the same frequency resource area or a case in which
one of the two symbols does not carry an RS, and the other symbol
includes an RS.
[0189] Herein, whether to apply time-axis or frequency-axis
precoding/beamforming is configurable. For example, with the same
precoding/beamforming on the time axis, the foregoing 1-symbol
PUCCH TxD method may be applied to each symbol, with the same
precoding/beamforming on the frequency axis, different
precoding/beamforming may be applied to each symbol, or with
different precoding/beamforming on the time axis, the foregoing
1-symbol PUCCH TxD method may be applied to each symbol.
[0190] The method described above in this section may be applied
commonly to the PUCCH structure with an RS and UCI multiplexed in
FDM, and the PUCCH structure transmitted without an RS by sequence
selection.
[0191] 3.2.3. Long PUCCH TxD Method
[0192] According to the present invention, no symbol may include an
RS in a long PUCCH in consideration of RS overhead. Accordingly,
precoding/beamforming may be applied in a different manner in
consideration of a symbol with an RS. Herein, as an RS and UCI are
multiplexed in time division multiplexing (TDM), there may be a
symbol with the RS only and a symbol with the UCI only.
[0193] For example, when frequency hopping is performed to achieve
a frequency diversity gain, different precoding/beamforming may be
applied per hop.
[0194] In another example, different precoding/beamforming may be
applied to each group of symbols carrying an RS. In a specific
example, in the presence of a plurality of RS symbols in one hop,
different precoding/beamforming may be applied even within the one
hop. If symbols are allocated in the order of UCI, RS, RS, and UCI
in one hop including four symbols, different precoding/beamforming
may be applied between the first two symbols and between the last
two symbols. In this case, as different precoders are used, an OCC
may not be applied between symbols over which a precoder is changed
within the same hop.
[0195] In another example, different precoding/beamforming may be
applied to a multi-slot long PUCCH on a slot or slot group basis
(preset or configured by L1 signaling or higher-layer
signaling).
[0196] As an exemplary method of including UCI in each
frequency/time resource to which a different precoder is applied,
the same coded bit may be repeatedly included or coded bits are
distributedly included in the foregoing 1-symbol PUCCH TxD method,
2-symbol PUCCH TxD method, and long PUCCH TxD method.
[0197] Meanwhile, only when a predetermined number of or more ports
are configured for PUCCH transmission (e.g., 4 ports are configured
for PUCCH transmission), the foregoing precoder cycling-based
1-symbol PUCCH TxD method, 2-symbol PUCCH TxD method, and long
PUCCH TxD method may be applied.
[0198] For example, a TxD method such as 2-port space frequency
block code (SFBC)/space time block code (STBC) may be applied to a
PUCCH, and a different precoder may be applied to each predefined
frequency/time resource set by using a different AP pair. In a more
specific example, when APs #1 and #2, and APs #3 and #4 are paired
respectively, a UE may apply SFBC to APs #1 and #2, and also to APs
#3 and #4. When the UE transmits a 2-symbol PUCCH, the UE may
transmit the PUCCH in the first symbol through APs #1 and #2, and
in the second symbol through APs #3 and #4, thereby separating the
AP pairs from each other in the time domain.
[0199] 3.3. UL RS and NR-PUSCH Transmission Method
[0200] In FIG. 9, APs used actually for NR-PUSCH transmission and
the positions of subcarriers carrying DM-RSs may be predetermined
or preset.
[0201] For example, regarding APs of each UE, the same AP numbers
may be assigned for an RS such as SRS/DM-RS(/PTRS) (e.g., for 4
APs, port numbers are assigned 1, 2, 3 and 4). In this case, it may
be configured that the SRS is transmitted through as many APs as
the number of APs reported by the UE. If the UE reports 4 APs, an
SRS transmission may be configured for APs #1, #2, #3, and #4.
[0202] Further, a resource to carry an RS sequence corresponding to
an AP number may be preset. In FIG. 9, a DM-RS and a PCRS may be
transmitted respectively in D1 and P1 through AP #1. Likewise, the
DM-RS and the PTRS may be transmitted respectively in D2 and P2
through AP #2, in D3 and P3 through AP #3, and in D4 and P4 through
AP #4.
[0203] Herein, if only an AP used actually for NR-PUSCH
transmission is indicated to the UE during UL scheduling, the UE
may attempt to transmit the DM-RS/PUSCH(/PTRS) by selecting only
the AP. Herein, a corresponding DM-RS(/PTRS) transmission resource
may be configured to be a resource corresponding to an AP number
scheduled in a predetermined rule.
[0204] In other words, although only one of information about an AP
used actually for NR-PUSCH transmission and information about the
position of a subcarrier carrying a DM-RS(/PTRS) is provided to the
UE, the UE may acquire the two pieces of information. Therefore, a
gain may be achieved in terms of signaling overhead during UL
scheduling.
[0205] For example, if an AP used actually for NR-PUSCH
transmission is indicated as #1 by DCI, the UE may transmit a DM-RS
on subcarriers #0, #4 and #8 through AP #1 as pre-agreed, without
additional signaling.
[0206] However, if both of UE1 and UE2 are scheduled to transmit
NR-PUSCHs through AP #1 in MU-MIMO UL transmission, the two UEs
transmit DM-RSs on the same subcarrier, thereby degrading channel
estimation performance. To avoid the problem, scheduling
restriction may result.
[0207] As a solution to the above problem, the present invention
proposes a method of transmitting a DM-RS/NR-PUSCH and a method of
indicating a transmission position for the DM-RS/NR-PUSCH. While a
configuration of the present invention is described below, focusing
on the DM-RS, for the convenience, the configuration may also be
applied to the PTRS.
[0208] 3.3.1. An AP Used for NR-PUSCH Transmission and the Position
of a Resource Carrying a DM-RS are Indicated Separately by DCI (or
Physical-Layer Signaling).
[0209] (1) An AP used for NR-PUSCH transmission and the position of
a resource carrying the DM-RS are indicated in respective
bitmaps.
[0210] If there are four APs, and a DM-RS is transmitted on a
different subcarrier through each AP as illustrated in FIG. 9, an
AP indication and the position of a resource carrying the DM-RS may
be signaled in a total of 8 bits, 4 bits for each. For example, if
APs used in the NR-PUSCH transmission are indicated as "1100" and
the positions of resources carrying the DM-RS are indicated as
"0011", the UE transmits an NR-PUSCH through APs #1 and #2, and
transmits the DM-RS on subcarriers #2, #6, and #10 through AP #1
and on subcarriers #3, #7 and #11 through AP #2.
[0211] (2) Only the positions of resources carrying a DM-RS are
indicated by a bitmap, and the offset of a starting AP number is
indicated.
[0212] For example, the positions of resources carrying the DM-RS
may be signaled as "1010" and the offset may be signaled as "1". An
offset value of "0" may indicate APs #1 and #2, an offset value of
"1" may indicate APs #2 and #3, and an offset value of "2" may
indicate APs #3 and #4. In the above example, therefore, the UE may
transmit the DM-RS through APs #2 and #3, specifically on
subcarriers #0, #4 and #8 through AP #2, and on subcarriers #2, #6
and #10 through AP #3.
[0213] (3) A set of APs used for NR-PUSCH transmission and/or a set
of the positions of resources carrying a DM-RS are limited to
predetermined candidates.
[0214] Signaling two pieces of information in bitmaps as in the
foregoing (1) may lead to large signaling overhead. In this
context, a method of reducing signaling overhead by limiting
candidate sets which may be indicated by each bitmap may be
considered.
[0215] For example, sets of APs available for NR-PUSCH transmission
may be limited to {1}, {2}, {3}, {4}, {1,2}, {3,4}, and {1,2,3,4},
and sets of the positions of resources carrying the DM-RS may be
limited to {D1}, {D2}, {D3}, {D4}, {D1,D2}, {D3,D4}, and
{D1,D2,D3,D4}. In this case, 3 bits is required to represent each
piece of information, and thus the two pieces of information may be
signaled in a total of 6 bits. Furthermore, the two pieces of
information may be jointly encoded, thereby reducing signaling
overhead. More specifically, the number of APs linked to an AP set
may be regarded as equal to that of the positions of resources
carrying the DM-RS. In this case, the information may be
represented as a total of 21 (=4.sup.2+2.sup.2+1) states, and thus
signaled by a 5-bit field in DCI.
[0216] (4) Antenna selection information such as information about
APs used for NR-PUSCH transmission (or information about the
positions of resources carrying a DM-RS) is transmitted by using a
codebook (or a precoding matrix).
[0217] For example, when the gNB indicates TxD transmission through
two APs selected from among APs #1, #2, #3, and #4, if a codebook
of
1 2 .function. [ 1 0 1 0 ] ##EQU00001##
is signaled, the UE may attempt to transmit an NR-PUSCH in TxD
through APs #1 and #3.
[0218] 3.3.2. A Different Mapping Relationship Between APs Used for
NR-PUSCH Transmission and the Positions of Resources Carrying a
DM-RS is Configured for Each UE by Higher-Layer Signaling (e.g.,
RRC Signaling).
[0219] For example, in the case where UE1 is configured to transmit
a DM-RS in resources D1, D2, D3, and D4 (in FIG. 9) through APs #1,
#2, #3, and #4, and UE2 is configured to transmit a DM-RS in
resources D4, D3, D2, and D1 through APs #1, #2, #3, and #4, even
though the gNB indicates MU-MIMO UL transmission through AP #1 to
each UE, the DM-RS of each UE may be transmitted in a different
frequency resource.
[0220] The configurations described in section 3.3.1. and section
3.3.2. may also be applied in the same rule to the PTRS (without
additional signaling). Or, an AP used for NR-PUSCH transmission,
the position of a resource carrying a DM-RS, and the position of a
resource carrying a PTRS may be indicated separately by additional
signaling other than the DM-RS.
[0221] In the configurations described in section 3.3.1. and
section 3.3.2., if the number of APs reported by the UE or the
number of APs actually indicated for transmission is N, it may be
allowed to indicate DM-RS/PTRS transmission through more than N
APs. For example, when N=2, DM-RS transmission through 4 APs may be
indicated. In this case, the UE may transmit the DM-RS on all
subcarriers in symbol #2 (according to a preset rule).
[0222] 3.3.3. Method of Using Resources Carrying No DM-RS for
NR-PUSCH Transmission
[0223] Meanwhile, if a DM-RS is transmitted in a different resource
through each AP as illustrated in FIG. 9, some resources may not be
used for either DM-RS transmission or NR-PUSCH transmission
according to APs used by the UE. For example, if one UE transmits
an NR-PUSCH only through one AP, three subcarriers out of four
subcarriers of symbol #2 in transmission resource areas of the UE
may not be used for transmitting a specific signal. In this
context, a specific method of allowing use of corresponding
resources for an NR-PUSCH in order to efficiently use radio
resources will be described in this section.
[0224] (1) Information about subcarriers carrying no DM-RS is
indicated by DCI (or physical-layer signaling).
[0225] If a DM-RS is transmitted on a different subcarrier through
each AP as illustrated in FIG. 9, the gNB may signal information
about subcarriers that do not carry the DM-RS to a UE by a 4-bit
bitmap. For example, if "0011" is signaled to the UE, the UE may
transmit the NR-PUSCH on subcarriers #2, #3, #6, #7, #10, and #11
in symbol #2.
[0226] (2) Resources that do not carry a DM-RS are used in a
different manner according to a transmission scheme of a UE.
[0227] If it is assumed that a TxD is not supposed to operate in
MU-MIMO, it may be determined implicitly whether the NR-PUSCH is
mapped to a subcarrier that does not carry the DM-RS (simply
without additional signaling). For example, it may be configured
that a UE scheduled with TxD transmits an NR-PUSCH by mapping the
NR-PUSCH to a subcarrier unused for DM-RS transmission, and a UE
scheduled with a transmission scheme other than TxD does not
map/transmit the NR-PUSCH to/on a subcarrier unused for DM-RS
transmission. Herein, it may be indicated implicitly whether the
DM-RS is to be transmitted by existing signaling.
[0228] (3) Method of indicating to a UE only whether scheduling for
the UE is "single UE scheduling" or whether "the NR-PUSCH is
mapped/transmitted to/on a subcarrier unused for DM-RS
transmission" irrespective of an NR-PUSCH transmission scheme
(e.g., single AP transmission, TxD, or SM).
[0229] In this case, if "single UE scheduling" or
"mapping/transmitting the NR-PUSCH to/on subcarrier unused for
DM-RS transmission" is indicated to the UE, the UE may map/transmit
the NR-PUSCH to/on a subcarrier unused for DM-RS transmission. On
the contrary, if "non-single UE scheduling" or
"non-mapping/non-transmission of the NR-PUSCH to/on subcarrier
unused for DM-RS transmission" is indicated to the UE, the UE may
not map/transmit the NR-PUSCH to/on a subcarrier unused for DM-RS
transmission.
[0230] (4) Power level applied to NR-PUSCH transmission method
[0231] In the present invention, a UE may attempt to transmit an
NR-PUSCH on a subcarrier unused for DM-RS transmission irrespective
of an NR-PUSCH transmission method (e.g., single AP transmission,
TxD, or SM). Or the UE may be configured to operate in the above
manner by RRC signaling.
[0232] Herein, if the NR-PUSCH is transmitted on subcarriers
available for DM-RS transmission, there may be a limit on
transmission power and/or an MCS. This is because other UEs may
potentially transmit DM-RSs on the subcarriers.
[0233] For example, the UE may transmit the NR-PUSCH with power
lower than NR-PUSCH power by P_offset (preset or configured by
higher-layer/physical-layer signaling). If there is a lower bound
on the NR-PUSCH transmission power, and the power value to which
P_offset has been applied is lower than the lower bound, the UE may
drop the NR-PUSCH transmission or transmit the NR-PUSCH with power
corresponding to the lower bound in a corresponding symbol.
[0234] In another example, a default modulation order for a symbol
available for DM-RS transmission may be set to 2 (binary phase
shift keying (BPSK)) (or a specific I_mcs value) (by
higher-layer/physical-layer signaling).
[0235] (5) Information indicating the position of the starting
symbol of an NR-PUSCH implicitly indicates whether "the NR-PUSCH is
transmitted on a subcarrier unused for DM-RS transmission".
[0236] If the position of the starting symbol of the NR-PUSCH is
signaled, NR-PUSCH transmission may be allowed on a subcarrier
unused for DM-RS transmission from the position of a symbol
configured with DM-RS transmission to the position of the starting
symbol of the NR-PUSCH. For example, if the starting symbol of the
NR-PUSCH is indicated as symbol #2, and DM-RS transmission is
indicated only for subcarriers corresponding to D1 and D2 in the
frame structure illustrated in FIG. 9, the UE may attempt to
transmit the NR-PUSCH on the other subcarriers corresponding to D3
and D4.
[0237] The configuration described in section 3.3.3. may also be
applied in the same manner to the PTRS (without additional
signaling). By additional signaling other than the DM-RS, it may be
indicated separately whether the NR-PUSCH is to be
mapped/transmitted to/on a subcarrier unused for PTRS transmission
(by physical-layer or higher-layer signaling).
[0238] 3.3.4. It is Configured Whether a Signal Such as a PTRS or a
DM-RS is Additionally Transmitted.
[0239] In consideration of high mobility, BS-UE
frequency/satellite/time tracking, or phase noise of an oscillator,
it may be necessary to additionally transmit a signal such as a
PTRS or a DM-RS to help with channel estimation. As the signal is
transmitted more times, channel estimation performance is improved,
thereby increasing signaling overhead and degrading the
transmission performance of PUSCH data. That is, there is a
tradeoff between the transmission performance of PUSCH data and
signaling overhead. In this context, it may be regulated that
whether a corresponding signal is to be transmitted additionally
(and/or information about the positions/density of resources to
carry the signal and/or the sequence of the signal) is configurable
by higher-layer signaling or L1 signaling.
[0240] However, it may also be regulated that when the UE attempts
initial access on a specific subcarrier, whether the signal (i.e.,
the PTRS and/or the additional DM-RS) is transmitted (and/or
information about the positions/density of resources to carry the
signal and/or the sequence of the signal) is also configurable for
a message 3 PUSCH (i.e., a PUSCH scheduled by a UL grant in a
random access response (RAR) transmitted in response to an RACH
transmission) in an RACH procedure. This signal configuration may
be indicated by a system information block (SIB) or an RAR
message.
[0241] Or, the configuration of the corresponding signal (i.e., the
PTRS and/or the additional DM-RS) (e.g., information indicating
transmission or non-transmission and/or information about the
positions/density of resources to carry the signal and/or the
sequence of the signal) may be indicated implicitly, not
explicitly. For example, when transmitting the message 3 PUSCH in a
specific frequency band (e.g., above 6 GHz), the UE may always
transmit the PTRS (or the additional DM-RS). In another example, in
the case where a signal is transmitted by analog beam sweeping,
when transmitting the message 3 PUSCH in a specific frequency band
(e.g., above 6 GHz), the UE may always transmit the PTRS (or the
additional DM-RS).
[0242] 3.3.5. PTRS Transmission Method for Supporting MU-MIMO
Between Cyclic Prefix (CP)-OFDM UE and DFT Spread OFDM UE
(DFT-s-OFDM UE)
[0243] To support MU-MIMO between a CP-OFDM UE and a DFT-s-OFDM UE
(or between DFT-s-OFDM UEs), it may be configured that the PTRS is
mapped to all subcarriers in a specific symbol (like the DM-RS).
Or, the UE may puncture an NR-PUSCH in REs to which the PTRS is to
be mapped after performing DFT on the NR-PUSCH, or performing DFT
with the number of REs except for the REs to which the PTRS is to
be mapped, at the expense of the PAPR of DFT-s-OFDM.
[0244] If multiplexing between the NR-PUSCH and the PTRS is
supported at the front end of DFT to maintain a low PAPR for the
DFT-s-OFDM UE, it may be indicated dynamically by a UL grant
whether the PTRS mapping is performed before or after DFT.
[0245] Specifically, when MU-MIMO is scheduled between a CP-OFDM UE
and a DFT-s-OFDM UE (or between DFT-s-OFDM UEs), the gNB may
indicate post-DFT PTRS mapping, and when an NR-PUSCH is scheduled
only for the DFT-s-OFDM UE, the gNB may indicate pre-DFT PTRS
mapping.
[0246] Now, a description will be given of a method of transmitting
a UL signal to a BS by a UE among the foregoing various signal
transmission and reception methods.
[0247] Specifically, when a UE according to the present invention
transmits a UL signal to a BS, the UE may transmit the UL signal by
using a different beamforming (i.e., precoder cycling) method for
each predetermined resource area carrying the UL signal.
[0248] To this end, the UE transmits the UL signal by applying a
different beamforming scheme to each of resource areas divided
according to a predetermined rule in one or more symbols of one
slot including a plurality of symbols.
[0249] The UL signal may be a PUCCH or PUSCH. While the following
description is given in the context of the PUCCH by way of example,
the same thing may apply to the PUSCH as another exemplary UL
signal.
[0250] Further, applying a different beamforming scheme to each of
resource areas divided according to the predetermined rule by the
UE may mean that the UE applies one or more of digital beamforming,
analog beamforming, and hybrid beamforming differently to the
respective resource areas.
[0251] For example, the UL signal may be transmitted in a 1-symbol
PUCCH structure. Then, the UE may transmit the 1-symbol PUCCH by
applying a different beamforming scheme to each of the resource
areas divided according to the predetermined rule.
[0252] For this purpose, the UE may receive information about the
predetermined rule from the BS. The information about the
predetermined rule may include one of information about the size of
frequency resources to which the same beamforming scheme is
applied, and information about a frequency resource range to which
the same beamforming scheme is applied.
[0253] Further, the UE may transmit the 1-symbol PUCCH by
distributedly mapping the 1-symbol PUCCH in the frequency domain
within one symbol. Herein, the UE may transmit the 1-symbol PUCCH
by applying a different beamforming scheme to each set of
contiguous frequency resources or each set of contiguous resources
of the same comb index in the one symbol carrying the 1-symbol
PUCCH.
[0254] In another example, the UL signal may be transmitted in a
2-symbol PUCCH structure.
[0255] Then, the UE may transmit the 2-symbol PUCCH by applying a
different beamforming scheme to each of symbols carrying the
2-symbol PUCCH.
[0256] In this case, the UE may transmit the 2-symbol PUCCH by
applying different beamforming schemes to a symbol carrying an RS
and a symbol without an RS among the symbols carrying the 2-symbol
PUCCH.
[0257] Or, the UE may transmit the 2-symbol PUCCH by applying a
different beamforming scheme to each frequency resource area of a
predetermined size in two symbols carrying the 2-symbol PUCCH.
[0258] In another example, the UL signal may be transmitted in a
PUCCH structure exceeding 2 symbols. This PUCCH structure will be
referred to as a long PUCCH.
[0259] In this case, the UE may transmit the long PUCCH by applying
different beamforming schemes to a symbol carrying an RS and a
symbol without an RS among symbols carrying the long PUCCH.
[0260] Or, when the UE transmits the long PUCCH by frequency
hopping, the UE may transmit the long PUCCH by applying a different
beamforming scheme to each hop in more than two symbols carrying
the long PUCCH.
[0261] Since examples of the above proposed methods may be included
as one of methods of implementing the present invention, it is
apparent that the examples may be regarded as proposed methods.
Further, the foregoing proposed methods may be implemented
independently, or some of the methods may be implemented in
combination (or merged). Further, it may be regulated that
information indicating whether the proposed methods are applied (or
information about the rules of the proposed methods) is indicated
to a UE by a pre-defined signal (or a physical-layer or
higher-layer signal) by an eNB.
4. Device Configuration
[0262] FIG. 18 is a diagram illustrating configurations of a UE and
a base station capable of being implemented by the embodiments
proposed in the present invention. The UE and the base station
illustrated in FIG. 18 operate to implement the embodiments of the
foregoing signal transmission and reception methods between a UE
and a BS.
[0263] A UE 1 may act as a transmission end on a UL and as a
reception end on a DL. A base station (eNB or new generation NodeB
(gNB)) 100 may act as a reception end on a UL and as a transmission
end on a DL.
[0264] That is, each of the UE and the base station may include a
Transmitter (Tx) 10 or 110 and a Receiver (Rx) 20 or 120, for
controlling transmission and reception of information, data, and/or
messages, and an antenna 30 or 130 for transmitting and receiving
information, data, and/or messages.
[0265] Each of the UE and the base station may further include a
processor 40 or 140 for implementing the afore-described
embodiments of the present disclosure and a memory 50 or 150 for
temporarily or permanently storing operations of the processor 40
or 140.
[0266] The UE 1 having the above configuration may transmit a UL
signal (e.g., NR-PUCCH or NR-PUSCH) in the following manner
[0267] Specifically, the UE 1 may transmit the UL signal, through
the transmitter 10, by applying a different beamforming scheme to
each of resource areas divided according to a predetermined rule in
one or more symbols of one slot including a plurality of
symbols.
[0268] Various rules may be available as the predetermined rule,
which divide a time/frequency resource area carrying the UL signal
into resource areas to which different beamforming schemes are
applied.
[0269] The Tx and Rx of the UE and the base station may perform a
packet modulation/demodulation function for data transmission, a
high-speed packet channel coding function, OFDM packet scheduling,
TDD packet scheduling, and/or channelization. Each of the UE and
the base station of FIG. 18 may further include a low-power Radio
Frequency (RF)/Intermediate Frequency (IF) module.
[0270] Meanwhile, the UE may be any of a Personal Digital Assistant
(PDA), a cellular phone, a Personal Communication Service (PCS)
phone, a Global System for Mobile (GSM) phone, a Wideband Code
Division Multiple Access (WCDMA) phone, a Mobile Broadband System
(MBS) phone, a hand-held PC, a laptop PC, a smart phone, a Multi
Mode-Multi Band (MM-MB) terminal, etc.
[0271] The smart phone is a terminal taking the advantages of both
a mobile phone and a PDA. It incorporates the functions of a PDA,
that is, scheduling and data communications such as fax
transmission and reception and Internet connection into a mobile
phone. The MB-MM terminal refers to a terminal which has a
multi-modem chip built therein and which can operate in any of a
mobile Internet system and other mobile communication systems (e.g.
CDMA 2000, WCDMA, etc.).
[0272] Embodiments of the present disclosure may be achieved by
various means, for example, hardware, firmware, software, or a
combination thereof.
[0273] In a hardware configuration, the methods according to
exemplary embodiments of the present disclosure may be achieved by
one or more Application Specific Integrated Circuits (ASICs),
Digital Signal Processors (DSPs), Digital Signal Processing Devices
(DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate
Arrays (FPGAs), processors, controllers, microcontrollers,
microprocessors, etc.
[0274] In a firmware or software configuration, the methods
according to the embodiments of the present disclosure may be
implemented in the form of a module, a procedure, a function, etc.
performing the above-described functions or operations. A software
code may be stored in the memory 50 or 150 and executed by the
processor 40 or 140. The memory is located at the interior or
exterior of the processor and may transmit and receive data to and
from the processor via various known means.
[0275] Those skilled in the art will appreciate that the present
disclosure may be carried out in other specific ways than those set
forth herein without departing from the spirit and essential
characteristics of the present disclosure. The above embodiments
are therefore to be construed in all aspects as illustrative and
not restrictive. The scope of the disclosure should be determined
by the appended claims and their legal equivalents, not by the
above description, and all changes coming within the meaning and
equivalency range of the appended claims are intended to be
embraced therein. It is obvious to those skilled in the art that
claims that are not explicitly cited in each other in the appended
claims may be presented in combination as an embodiment of the
present disclosure or included as a new claim by a subsequent
amendment after the application is filed.
INDUSTRIAL APPLICABILITY
[0276] The present disclosure is applicable to various wireless
access systems including a 3GPP system, and/or a 3GPP2 system.
Besides these wireless access systems, the embodiments of the
present disclosure are applicable to all technical fields in which
the wireless access systems find their applications. Moreover, the
proposed method can also be applied to mmWave communication using
an ultra-high frequency band.
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